• ** REMEMBER! **The microwave can still shock you even unplugged!!

    ALWAYS discharge the high-voltage capacitor first if you even think your hands will come close to any HIGH VOLTAGE components.

    Jeff mentions this: Anything in the high voltage ( magnetron, capacitor, diode, wires to and from ):
    ...Use a metal ( not the shiny chrome type ) screw driver with a insulated handle to short across ( touch both at the same time ) the terminals of the high voltage capacitor to discharge it.

    From Jeff's site: http://www.applianceaid.com/component-testing.php

    Jake
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FIXED Whirlpool WMH32517AB, Electrical sparks when first turning on the microwave

Paulseclipse

Premium Member
Joined
Oct 25, 2016
Messages
9
Location
Florida
Model Number
WMH32517AB
Brand
Whirlpool
Age
1-5 years
I started hearing electrical sparks when first turning on the microwave from around the control panel area. I removed the top vent panel and found it to be a cracked diode from the capacitor causing arcing to the other insulated lead. I bought a new diode of the same spec but had a different connector so I soldered on the old one. Turned on the microwave and blew the fuse after a second. I thought maybe it was the diode even tho it tested fine using a 9 volt. I decided to try the exact diode from the manufacturer and same thing blew the fuse. I tested the capacitor and it seems to be okay with dropping voltage from the mutlimeter.

I am confused why the old cracked diode while sparked at start up would work fine but the new ones blow the fuse. Any idea what could be causing the issue? Thank you for any input you can give. I hope it's not the transformer or mag that are so expensive compared to a new microwave. Thank you again.
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
37,052
Location
Murray, Utah 84107, United States
Check and make sure you have it wired correctly. Make sure the diode is in the correct position. Measure from the mag tube terminals to ground and see if it's shorted. Check the resistance of the high voltage transformer windings.
C-Microwave HV.jpg

Here's the OEM diode for your model:
Whirlpool W10492278 Diode
 

Paulseclipse

Premium Member
Joined
Oct 25, 2016
Messages
9
Location
Florida
Okay so today I had some spare time to test all the components that are obvious and I'm at a loss. They all seem fine.....please check my data and see if you can help me solve this.

Capacitor terminal to terminal on 200 ohm setting reads nothing
Capacitor each term on 20k reads nothing
2 diodes tested with 9v battery.....battery reads 9.52 on its own.
Each diode reads 0 one way and 4.82 the other.
Mag terminal to terminal on 200 ohm setting reads .3 ohms.
Mag each terminal on 20k setting to ground nothing.
Transformer primary 200 setting reads .6
Transformer 20k setting primary each terminal reads open.
Transformer secondary 200 setting .5 terminal to terminal.
Transformer secondary 20k setting to ground open.
Transformer high voltage to ground 82.5 reading.

Fuse continuity test fine.

2x door switches continuity test one read fine open and other closed.

Any other ideas?
 

Paulseclipse

Premium Member
Joined
Oct 25, 2016
Messages
9
Location
Florida
Pure and simple.....stupidity on my part.......i marked the wires on paper and somehow wrote it down wrong. The diode was hooked to the wrong capacitor terminal.

Diode was the issue and everything works fine now. At least I learned all about the major microwave components that I have never dealt with till recently.

Thank you for the input while I'll continue to smh.
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
37,052
Location
Murray, Utah 84107, United States
I had a feeling it was something like that. Been there, done that. How did you find it?
 

Paulseclipse

Premium Member
Joined
Oct 25, 2016
Messages
9
Location
Florida
Once everything else tested fine I figured it had to be something with the diode and only thing left was to swap it to the other terminal so I just went for it and sure enough it was on the wrong one.
 
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